1. Field of the Invention
The present invention relates to a relative positioning machine for positioning two members which support a machining tool and a workpiece, respectively, for example, relatively to each other universally in two- and three-dimensional spaces before the two members act with each other, e.g., the machining tool machines the workpiece.
2. Description of the Related Art
Various machine tools are used in the art to machine, e.g., drill, mill, or grind, workpieces with drill bits or cutters.
FIG. 37 of the accompanying drawings shows a conventional machine tool 1 having a spindle 2 rotatable about its own axis and reciprocally movable vertically in the directions indicated by the arrow A. A drill bit 4 is mounted on the spindle 2. A workpiece W is supported on a base 5 and has a plurality of areas 6a.about.6n to be successively aligned with and drilled by the drill bit 4.
In operation, the spindle 2 and the drill bit 4 are rotated in unison with each other, and moved downwardly toward the workpiece W to drill one of the areas 6a.about.6n, e.g., the area 6a, with the rotating drill bit 4. After the area 6a has been drilled, the spindle 2 is elevated to lift the drill bit 4 off the workpiece W. Thereafter, the spindle 2 is horizontally moved a predetermined distance in one of the directions indicated by the arrows B, C until the drill bit 4 is vertically aligned with another one of the areas 6b.about.6n, e.g., the area 6b. Then, the spindle 2 and the drill bit 4 are rotated in unison with each other, and moved downwardly toward the workpiece W to drill the area 6b with the rotating drill bit 4. In this manner, the areas 6a.about.6n of the workpiece W are successively drilled by the drill bit 4.
For successively drilling the areas 6a.about.6n of the workpiece W, it is necessary to horizontally move the spindle 2 a predetermined distance in one of the directions indicated by the arrows B, C to bring the drill bit 4 into vertical alignment with one of the areas 6a.about.6n each time it is to be drilled. Since the machine tool 1 is considerably heavy, it develops a large inertia when it is horizontally moved. Therefore, a high-power actuating mechanism is required to horizontally move the machine tool 1, and it is highly difficult or almost impossible to quickly position the machine tool 1 into vertical alignment with one of the areas 6a.about.6n.
The process of positioning the drill bit 4 and the workpiece W with respect to each other is made all the more complicated if the areas 6a.about.6n are to be drilled to form holes that are inclined in various directions. Drilling such inclined holes in the workpiece W is quite an inefficient task to perform.
The above positioning problem also occurs in other machining operations including applying a laser beam to form a hole in a workpiece, to cut a workpiece, and to weld workpieces, and applying a water jet to machine a workpiece in various ways.